[meteorite-list] Timing is Everything
Thanks to Mike Jensen for the heads-up on the paper newly published by Dr. Jeff Grossman and Adrian Brearley refining the measurement of classification for chondrites. In the last couple of days, including today, I've been working on a feature for Meteorite magazine that includes discussions I had with Dr. Brigitte Zanda, the curator of the NHM met collection in Paris about her research in chondrule formation. We talked about her discovery of chondrules in a plastic state during formation in Semarkona LL3.0, perhaps the most primitive chondrite. The most obvious point here is that chondrules were observed in formation that are not spheres. It's an exciting discovery in today's most happenin' meteorite research area - the origins of chondrules. You can read more of this discussion in Meteorite come August. One side area of interest with all this, is that petrology is now determined by using thermaluminesence. This technique is a bit more sophisticated than when one looks at a slice of something and expertly guesses, Oh, that looks like a L5. A discussion has risen about thermaluminesence measuring because it's possible that terrestrial weathering can alter the outcome of a pre-terrestrial event, changing what observers think is a most primitive 3.0 to a 3.2 or 3.4. On my first quick read of this (I have a meeting in 30 minutes), Jeff and Adrian's paper seems to propose extremely accurate measuring of petrology in type 1 chondrules by combining electron microscopy and cathodoluminescence in their observations. The resultant measurements would be several times more accurate than present thermaluminesence techniques, i.e. resulting in petrology's of 3.05, 3.10, etc., instead of just 3.0 or 3.2. However, I'm assuming that cathodoluminescence (can't type that too many times without misspelling) is different from thermaluminesence (and I'm sure someone will soon let me know if it isn't - smiley face here). But this is great work and seems to me to be exciting news. Kevin Kichinka __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Timing is Everything
Thanks Kevin, it helps clarify[slightly] an issue that's screaming for investigation. Jerry Flaherty - Original Message - From: [EMAIL PROTECTED] To: meteorite-list@meteoritecentral.com Sent: Wednesday, April 20, 2005 4:52 PM Subject: [meteorite-list] Timing is Everything Thanks to Mike Jensen for the heads-up on the paper newly published by Dr. Jeff Grossman and Adrian Brearley refining the measurement of classification for chondrites. In the last couple of days, including today, I've been working on a feature for Meteorite magazine that includes discussions I had with Dr. Brigitte Zanda, the curator of the NHM met collection in Paris about her research in chondrule formation. We talked about her discovery of chondrules in a plastic state during formation in Semarkona LL3.0, perhaps the most primitive chondrite. The most obvious point here is that chondrules were observed in formation that are not spheres. It's an exciting discovery in today's most happenin' meteorite research area - the origins of chondrules. You can read more of this discussion in Meteorite come August. One side area of interest with all this, is that petrology is now determined by using thermaluminesence. This technique is a bit more sophisticated than when one looks at a slice of something and expertly guesses, Oh, that looks like a L5. A discussion has risen about thermaluminesence measuring because it's possible that terrestrial weathering can alter the outcome of a pre-terrestrial event, changing what observers think is a most primitive 3.0 to a 3.2 or 3.4. On my first quick read of this (I have a meeting in 30 minutes), Jeff and Adrian's paper seems to propose extremely accurate measuring of petrology in type 1 chondrules by combining electron microscopy and cathodoluminescence in their observations. The resultant measurements would be several times more accurate than present thermaluminesence techniques, i.e. resulting in petrology's of 3.05, 3.10, etc., instead of just 3.0 or 3.2. However, I'm assuming that cathodoluminescence (can't type that too many times without misspelling) is different from thermaluminesence (and I'm sure someone will soon let me know if it isn't - smiley face here). But this is great work and seems to me to be exciting news. Kevin Kichinka __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Timing is Everything
Hi Kevin and all, Excellent post! I have long wondered if weathering can play a factor in classification scheme, and other vital understanding of events in meteorites. I have even wondered if this could result in a false age prediction of specimens that have been on the ground (although a different animal :-), weathering-aging. Best! --AL Mitterling [EMAIL PROTECTED] wrote: A discussion has risen about thermaluminesence measuring because it's possible that terrestrial weathering can alter the outcome of a pre-terrestrial event, changing what observers think is a most primitive 3.0 to a 3.2 or 3.4. __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
